/* 页面左侧主要导航 */
.main-menu {
    display: flex;
    flex-direction: column;
    height: 100%;
    width: 20%;
    min-width: 20%;
    background-color: slategray;
    color: ghostwhite;
}

.main-menu  a {
    color: ghostwhite;
    text-align: center;
    padding: 1em;
    font-size: 1.5em;
}

.about-menu {
    width: 100%;
    margin: 0;
    padding: 0;
    list-style-type: none;
    display: flex;
    background-color: slategray;
}

.about-menu > li {
    flex-grow: 1;
}

.about-menu > li > a {
    display: block;
    width: calc(100% - 1em);
    text-align: center;
    text-decoration: none;
    color: ghostwhite;
    padding: 0.5em;
}
